The so-called Castelón de Illano forms part of the dense network of settlements that served as an organizational model for the distribution of the population and the optimal exploitation of the area's gold resources during the Early Roman Empire.

Illano Hill fort presents the most characteristic features of this type of settlement: terracing, defensive ditch and wall.

With the decline of mining, hill forts also took a downturn that was to end with their total abandonment, interrupted only by occasional re-occupation

The semi-circular houses in this pre-Roman settlement are spread about. There are remains of three houses on the upper plateau. Around the houses, there are some circular stones.

The northeastern area is spread over two terraces, the top one coinciding with the summit. The remains of three houses can be seen here built of overlapping slate slabs joined with clay which curve inward at the top, similar to that of the housing in Coaña Hill Fort, reminiscent of a vaulted roof.

More difficult to interpret is the lower terrace with a bow-shaped wall that converges towards the supposed gateway.